(506e) Improved CO2 Selectivity-Uptake Trade-Off Driven By Synergetic Thermodynamics, Kinetics, and Packing Effects

Improved CO₂
selectivity-uptake trade-off driven by synergetic thermodynamics, kinetics, and
packing effects

Youssef Belmabkhout^a, Weibin Liang^a, Prashant Bhatt^a, Aleksander
Shkurenko^a, Karim Adil^a, Georges Mouchaham^a,
Himanshu Aggarwal^a, Arijit Mallick^a, Aqil Jamal^b,
Mohamed Eddaoudi^a

^aFunctional Materials Design, Discovery &
Development (FMD3), Advanced Membranes and Porous Materials Center,
Division of Physical Sciences and Engineering, King Abdullah University of
Science and Technology, 4700 King Abdullah University of Science and Technology
(KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.

^b ARAMCO, R-GC 335, Floor 3, Research and Development Center (Bldg. 2297) Dhahran, Kingdom of Saudi Arabia

In this work, we report the deliberate use of the interpenetration
approach to develop a new, fluorinated MOF with the appropriate pore system
(size, shape, and functionality) to enhance the efficient capture of CO₂
from flue gas at room temperature. The MOF, dptz-CuTiF₆, exhibits
excellent volumetric and gravimetric CO₂ uptakes (65.6 cm³
g^-1 and 0.13 g g^-1) at 10% CO₂ and 298 K,
which is superior to those of the reference, aqueous amine, with a
significantly lower energy input for regeneration (38 kJ mol^-1versus
105 kJ mol^-1). In cyclic adsorption breakthrough experiments,
dptz-CuTiF₆ achieves complete CO₂ desorption at 298 K
under inert gas purging. Single-crystal X-ray diffraction studies demonstrate
that the exceptional CO₂ adsorption capacity, moderate CO₂
heat of adsorption, and high CO₂/N₂ selectivity are due
to the optimal packing of the CO₂ molecules within the MOF, as well
as the favorable thermodynamics and kinetics from cooperative host-guest
interactions.

Figure
1. Evolution of
fluorinated, microporous metal-organic frameworks (MOFs) as CO₂
adsorbents for flue gas treatment, showing the CO₂ adsorption
capacity (g g^-1) at 298 K and the CO₂isosteric
heat of adsorption (Q_st, kJ mol^-1)
for the first generation (SIFSIX-3-Zn
and SIFSIX-3-Cu) and second
generation materials (NbOFFIVE-1-Ni
and AlFFIVE-1-Ni), as well as the
envisioned features of the third generation materials.